'Consists' was not a meaningful term pre-TOPs, its more likely to be formations or rosters.

GE Section carriage workings are rarer than snakes legs or rocking horse output; I have one for January 1931 country districts but that only begins to make sense if you also know the old GE carriage codes, which are not included in the document.

I'm not aware of anything available through the GER Society or the LNER Society. The formations would in any event have been by type and accommodation and anything that more or less fit the requirement would have been used except for specific workings e.g. the continental boat trains.

I've been looking for this type of information for the East Suffolk line for a while. There is a complete dearth of it in any public or published source. All you can do is look at photographs and extrapolate sensibly.